These aren't the OS specific folders (ie Documents, ProgramData etc) I am trying to exclude, but folders I've created myself, outside any OS specific folders.
ie: D:\myfolder1
Sorry, I missunderstood your question, but the issue is still the same. Windows will affirm to the exclusion settings in Indexing Options. Any excluded folders wont show up in the Recent Documents, or as Windows 11 calls it, Recommended section